Release Selector

This command configures the tree in preparation for doing a staging release, and pushes the result to try. The changes that that are made include:

  • Updating the version number.

  • Applying the migrations that are done as part of merge day.

  • Disabling repacking most locales. (This can be disabled by passing --no-limit-locales).

For staging a beta release, run the following (with an appropriate version number):

$ mach try release --version 64.0b5 --migration central-to-beta

For staging a final release (rc or patch), run the following (with an appropriate version number)

$ mach try release --version 64.0 --migration central-to-beta --migration beta-to-release

Once the decision task is on the push is complete, you can start the release through staging ship-it instance1.


If pushing from beta or release, the corresponding migration should not be passed, as they have already been applied.


This is only available to release engineering and release management (as of 2018-10-15).